35d worsening gas mileage - solved- thermostat/fan/EGR cooler - DIY with pics

[bawareca]

I know nothing about Magnusson-Moss act, but i dare you to try. I can assure you there is not 1 hour warranty or return options for electronic parts if you take it out of the dealer not installed. There are a lot of electronic parts in the transmission, so in a case of failure it could swing either way. BMW will claim it was programmed incorrectly when first installed and nor Magnusson neither Moss could prove the opposite.
Everyone is free to believe what he wants, i just like to warn you that these are not all unconditional warranties.

[lanbrown]

Originally Posted by bawareca

I know nothing about Magnusson-Moss act

Then why make such profound statements?

I can assure you there is not 1 hour warranty or return options for electronic parts if you take it out of the dealer not installed.

Please provide proof of your assurance.

There are a lot of electronic parts in the transmission, so in a case of failure it could swing either way. BMW will claim it was programmed incorrectly when first installed and nor Magnusson neither Moss could prove the opposite.

How do you know, above you stated that you know nothing of the Magnusson-Moss act.

QUOTE]Everyone is free to believe what he wants, i just like to warn you that these are not all unconditional warranties.[/QUOTE]

How it it a warning when you first state that you know nothing of the Magnusson-Moss act. Then you say that you can assure that there is no warranty at all on electronic parts if the dealer doesn't install them but provided absolutely no proof at all. Before you were stating that BMW parts had no warranty unless installed by the dealer, which has been proven false.

[ZetaTre]

Originally Posted by jpeytonii

Funny you should mention this... The bigger concern with the transmission cooler thermostat is (if I am reading the hose diagrams correctly) that if it fails open it will allow coolant to flow through the radiator and back into the engine - bypassing the main thermostat.

I recently had the main thermostat replaced (after arguing with the dealer for two weeks that it was bad - "can't be bad if there are no codes...") and immediately our temperatures went from 65-70C to 89-91C. This was in a Chicago winter and I was monitoring it one day with ambient at 4F and driving on the interstate it stayed steady at 89-91C (it would go a few degrees higher during DPF regen). We are now a few months later and the temperature has dropped to ~84C while cruising on the highway. In town it will creep up to around 90C. Theses are the classic signs to me that coolant is prematurely passing through the radiator. My next step is to replace the transmission cooler thermostat.

There have been many posts in this thread asking what the proper coolant temp is. Since these engines use an old school thermostat that is designed to begin to open at 88C the proper temps to look for are slightly above that - i.e. 89-91C. Anything less than that is an indication that "cooled coolant" is being sent to the engine before it is warranted and you have a failed or failing thermostat. Then the question becomes: "which one?"

Cheers.

Actually, the only reason why I threw the transmission heat exchanger thermostat in the mix it is simply because it is a similar design as the one on the EU version of the EGR cooler (which is prone to failure) and because BMW is generally challenged with thermostats.

But in any case, if you do go ahead and replace it, let us know how it turns out.

[JGard]

So for those of you who have had your X5s a while, what would you consider poor fuel economy?

I noticed, based on my gauge, over about 50 miles worth of mostly highway, that I was only averaging low to mid 23s. At one point it was up to 24.1 but as the highway turned a little more uphill it dropped back to the low 23s. I may have mentioned already that I've monitored my coolant temp and it never eclipses 80C, but I wasn't sure if that was cold enough to really effect fuel economy.

On the bright side, when I'm commuting, and thus sitting in lots of traffic, my mileage is right around 22, so it's not a lot worse than my highway mileage.

[bawareca]

^^This my experience mostly. 23-25 mpg @75-80mph.
I have a feeling that the sport package 20" wheels cost 1-3 mpg.

[JGard]

Gotcha. I have the sport package with 19" wheels, but yes, I was also cruising around 70-75mph

[JGard]

Finally got around to doing this. Thank you, BMW, for making a simple thermostat a 4 hour job :|

Anyway, the process wasn't overly complex. I tried harder to find a large coolant line than I needed to, so that was wasted time. Then I found I took more of the intake off than was necessary, which also wasted time.

Note to those thinking about it. Those two flange bolts for the EGT cooler really are as tricky as you have read. Be careful and good luck. Also, the transmission cooling thermostat is SO easy to replace once you're in there, so cough up the extra $80 for that part and just do it to be safe. Once the fan is out, 3 10mm bolts and a clipped in line is all you have to replace.

[rippjd]

Originally Posted by jpeytonii

Not correct. BMW's parts warranty is 2 years unlimited mileage providing the part was purchased from an authorized BMW dealer. It does not matter who does the installation thought I am sure anything obviously cocked up would be excluded. Labor for the warranty repair is covered if it is performed at a authorized BMW center. All is explained in SI B01 01 14.

Cheers.

I'd rather the thread stay on topic... but I think the attached document is of some value to the DIY person... and I'm not on the forums often.
I bought a BMW battery over the counter at one Dealer, installed and registered myself. 2 years later it would not hold a charge. I drove the BMW to a different dealer, handed them a copy of the parts invoice and the attached Parts Warranty. They performed diagnotics, installed a new battery, registered it and I walked out with no bill. So Parts and Labor were covered on a part I bought and installed. It's possible this would have occured without the attached PDF, but I doubt it.

Note the language of "date of sale or installation". Good luck!

[Dr. Anthony]

Just wanted to bump up the thread with my story.

I decided to test this out myself.

Outside temp was 6degrees celcius
I drove about 30 minutes before doing the test, so it was on a warm motor. It started off at 71 then slowly climbed to 88-89 (took about 15 minutes of idling)

Then I drove onto the freeway for about 20 minutes with the cruise on 110km/h (68 mph)

The temps immediately dropped down to 70-71.
I just ordered a new t-stat, and so it'll probably get done sometime later this week. I'll update the thread again with my findings.

Current fuel mileage (according to my cluster) 8.6L/100 (~27.35 US MPG)
20" Nurburgring RF wheels

[ZetaTre]

Originally Posted by Dr. Anthony

Just wanted to bump up the thread with my story.

I decided to test this out myself.

Outside temp was 6degrees celcius
I drove about 30 minutes before doing the test, so it was on a warm motor. It started off at 71 then slowly climbed to 88-89 (took about 15 minutes of idling)

Then I drove onto the freeway for about 20 minutes with the cruise on 110km/h (68 mph)

The temps immediately dropped down to 70-71.
I just ordered a new t-stat, and so it'll probably get done sometime later this week. I'll update the thread again with my findings.

Current fuel mileage (according to my cluster) 8.6L/100 (~27.35 US MPG)
20" Nurburgring RF wheels

Look around for a post from ninja_zx10 on the proper tightening sequence of the EGR cooler. Make sure you follow it.

I'd also suggest you put some anti-seize on the bolts and the mating surface on the exhaust manifold side of the EGR cooler to ensure the bolts don't get stuck in the cast iron. In my case I put the anti-seize on the bolts, drove them through first and then recoat them before installing the cooler.

You don't need to disconnect any of the vacuum lines on the EGR cooler. You can simply flip it up and out of the way.



One side of the thermostat connects to a rigid line that goes towards the driver side around the head and under the throttle valve. There is bolt under the throttle valve that hold that line. It may help to release that bolt to get a bit more slack out of the rigid line.

Some of these things may not make lots of sense now, but keep them in mind as they will become clear once you're in there.